THE GEOLOGICAL AGE OF CENTRAL AND WEST CORNWALL. 181 

 TRILOBITA. 



(See Salter, Pal. Soc. 1862-1867 ; and Murchison, 

 " Siluria,'' 5th M., 1872). 



1 . Homalonotm bisulcatus. This species is said by both. Salter 



and Murchison to occur iu all the rocks from the 

 Loiver LlandeUo to the Caradoc. 



2. IT. Vidcani. This is also said to be Llandeilo. 



3. H. Sp. from Gorran Haveu. The specimen is now in 



Jermyn Street, and Salter (Pal. Soc. 1864, p. 112), 

 considers it to be a Lower Llandeilo form. 



4. Phacops apiciilatus. {Salt.) Specimens from Great Peraver 



and Gorran Haven are in the Museum, at Jermyn Street. 

 Murchison considers the species to be one characteristic 

 of the Caradoc, but Salter — who is, on this point, a far 

 more reliable authority — gives the horizon as Llandeilo 

 Flags. 



5. Phacops mirnus. Specimen believed to be from Great 



Peraver is in the Jermyn Street Museum, and labelled 

 Caradoc. Salter includes under this name all the fossils 

 formerly described as P. minitmis, and refers the species 

 to the Llandeilo flays. 



6. Cahjmene dupUcata. This is said by Murchison to be very 



typical of the Llandeilo flags at Builth. 



7. C. Tristani [Brong.) Specimens from Gorrau Haven and 



" Mevagissey " are in the Museum at Jermyn Street, 

 and are called '■'■ Arenig''^ by both Murchison and 

 Salter. 



8. C. Blumenhachii. This fossil has a very wide range in the 



Silurian system, as it is common both in the Caradoc and 

 in the Wenloclc, and specimens have been found even in 

 the Upper Ludloiv. 



8a. C. pulchella. Considered by Salter to be a mere variety 

 of G. Blumenlachii. 



9. G. hrevicapitata (Portlock.) Murchison regards this as 



identical with C, senaria ( Conrad), which is certainly a 

 Caradoc and Bala fossil. Salter, on the other hand, 

 agrees with the specific reference but includes it in his 

 var. Camhrensis {Salt.) which is typically Llandeilo. 



